py3: add __pycache__ to .hgignore
Something changed with Python 3 just like million on things. Maybe they should
named Python 3 as anaconda or cobra instead of just increasing the version
number.
This makes test-custom-filters.t pass on Python 3.
Differential Revision: https://phab.mercurial-scm.org/D5039
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}